Furnace-grate.



No. 723,622. PATENTED MAR. 24, 1903..' G. P. &- G. P. ROBERTS. FURNACEGRATE.

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UNITED STATES PATENT OFF-ICE...

CLARENCE PERCIVAL ROBERTS AND GEORGE PERCI VAL ROBERTS, OF TOLEDO, OHIO,ASSIGNORS OF ONE-HALF TO SINCLAIR BERDAN, OF

TOLEDO, orno.

FURNACE-G RATE.

SPECIFICATION forming part of Letters Patent No. 723,622, dated March24, 1903. 7

Application filed May 8, 1902.

To all whom it may concern:

Be it known that we, CLARENCE PERCIVAL ROBERTS and GEORGE PERCIVALROBERTS, citizens of the United States, and residents of Toledo, inthecounty of Lucas and State of Ohio, have invented a new and ImprovedFurnace-Grate, of which the following is a full, clear, and exactdescription.

This invention relates to improvements in grates for steam-boilerfurnaces, the object being to provide a grate of hollow bars throughwhich atmospheric air may pass and become heated before it meets withthe products of combustion..

WVe will describe a furnace-grate embodying our invention and then pointout the novel features in the appended claim.

Reference is to be had to the accompanying drawings, forming a part ofthis specification, in which similar characters of reference indicatecorresponding parts in all the figures.

Figure 1 is a longitudinal section of a furnace, showing a grateembodying our invention. Fig. 2 is a transverse section thereof. Fig. 3is a front elevation of the f urnace, and Fig. 4 is a longitudinalsection of one of the grate-bars.-

The grate-bars consist of tubes 1, whichpass through openings in thefront wall 2 of the furnace, and at their inner ends they communicatewith a chamber'3, formed in the bridge-wall 4, and the top of thebridge-wall is provided with openings 5, through which the heated airreceived from the tubular gratebars may pass and mingle with theproducts of combustion. The openings 5are the full width of the chamber,so that by such free outlet the air will not be retarded in the chamber,but will mix in large quantities with the products of combustion. Theamount of air entering the tubes may be regulated by means of a damper6, mounted to slide in guides 7, arranged on the front of the furnace,and this damper is provided with openings 8 to be moved into alinementwith the open ends of the tubular grate-bars 1 to close the same more orless, as may be desired. On one end of the damper 6 is arranged anoperating-lever 9.

To prevent the burning out of the'tubular grate-bars, we cover them witha material Serial No. 106,399. (No model.)

not affected by heat to any considerable extent. This material mayconsist of asbestos, cement, or other refractory material 9 A secondarygrate consisting of bars 10 of ordinary construction is arranged belowthe grate bars 1, the distance between the two grates being sufficientto give access through the ash -.pit door both to the surface of thesecondary grate and to the ash-pit. The purpose of this secondary grateis to maintain a slow incandescent fire, which is supplied almostentirely by drippings from the upper grate. The heat arising from thematerial on the secondary grate will keep the tubular grate-bars heated,and consequently heat the air passing through the same, and the heatedair passing between the-uppergrate-bars will pass through the main bedof fuel thereon and consume the smoke, the draft being maintainedthrough the space between the bridge-wall and boiler, because thebridgewall is entirely closed at the inner end of the grate-bars orbetween. the upper and. lower bars.

Having thus described our invention, we

claim as new and desire to secure by Letters -Patent .top of thebridge-wall which is spaced from the boiler in the furnace, said outletsbeing the full width of the chamber, tubular gratebars leading from saidchamber through the front wall of the furnace, covering of refractorymaterial for the bars and grate-bars arranged below the tubular bars,the said bridge-wall being closed at the inner ends of the two sets ofgrate-bars, whereby air heated by fire on the lower grate-bars will passthrough the bed of fuel on the upper tubular bars, substantially asspecified.

In testimony whereof we have signed our names to this specification inthe presence of two subscribing witnesses.

CLARENCE PERCIVAL ROBERTS. GEORGE PERClVAL ROBERTS.

